This project is designed to explore the effects of the administration of neurotrophic substances on recovery from brain damage. Nerve growth factor (NGF) will be used to facilitate behavioral recovery in rats given bilateral lesions of the caudate nucleus, limbic system or brain stem. We are particularly interested in whether the effects of such treatments are age-dependent and therefore we are giving NGF to animals at different points along the developmental spectrum. We also paln to examine the effects of intracerebral administration of polyamines in rats with lesions of the entorhinal cortex. In previous experiments we have been able to demonstrate that neurotrophic substances do, in fact, facilitate behavioral recovery and we hope to extend these results to aged subjects.